1649811920 has 40 divisors (see below), whose sum is σ = 4061452104. Its totient is φ = 621105152.

The previous prime is 1649811913. The next prime is 1649811929. The reversal of 1649811920 is 291189461.

It can be written as a sum of positive squares in 4 ways, for example, as 788037184 + 861774736 = 28072^2 + 29356^2 .

It is a tau number, because it is divible by the number of its divisors (40).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1649811929) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 605189 + ... + 607908.

Almost surely, 2^1649811920 is an apocalyptic number.

1649811920 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1649811920 is an abundant number, since it is smaller than the sum of its proper divisors (2411640184).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1649811920 is a wasteful number, since it uses less digits than its factorization.

1649811920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1213127 (or 1213121 counting only the distinct ones).

The product of its (nonzero) digits is 31104, while the sum is 41.

The square root of 1649811920 is about 40617.8768524402. The cubic root of 1649811920 is about 1181.6208502373.

The spelling of 1649811920 in words is "one billion, six hundred forty-nine million, eight hundred eleven thousand, nine hundred twenty".